U.S. patent application number 14/507841 was filed with the patent office on 2015-08-20 for head-up display.
This patent application is currently assigned to CORETRONIC CORPORATION. The applicant listed for this patent is Chi-Tang Hsieh, Hsin-Wen Tsai, Chung-Ting Wei. Invention is credited to Chi-Tang Hsieh, Hsin-Wen Tsai, Chung-Ting Wei.
Application Number | 20150234458 14/507841 |
Document ID | / |
Family ID | 53798116 |
Filed Date | 2015-08-20 |
United States Patent
Application |
20150234458 |
Kind Code |
A1 |
Hsieh; Chi-Tang ; et
al. |
August 20, 2015 |
HEAD-UP DISPLAY
Abstract
A head-up display including a display panel, a non-mechanical
focusing lens, and a determining unit is provided. The display
panel is configured to emit an image beam. The non-mechanical
focusing lens is disposed on a transmission path of the image beam
and generates an image of the image beam. The determining unit is
electrically connected to the non-mechanical focusing lens and
configured to adjust a focal length of the non-mechanical focusing
lens according to a sensing signal, so as to change an image
distance from the image to a user's eye.
Inventors: |
Hsieh; Chi-Tang; (Hsin-Chu,
TW) ; Wei; Chung-Ting; (Hsin-Chu, TW) ; Tsai;
Hsin-Wen; (Hsin-Chu, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hsieh; Chi-Tang
Wei; Chung-Ting
Tsai; Hsin-Wen |
Hsin-Chu
Hsin-Chu
Hsin-Chu |
|
TW
TW
TW |
|
|
Assignee: |
CORETRONIC CORPORATION
Hsin-Chu
TW
|
Family ID: |
53798116 |
Appl. No.: |
14/507841 |
Filed: |
October 7, 2014 |
Current U.S.
Class: |
345/156 |
Current CPC
Class: |
B60K 35/00 20130101;
B60K 2370/149 20190501; G02B 27/0101 20130101; G02B 27/0172
20130101; B60K 2370/1529 20190501; B60K 2370/334 20190501; G02B
2027/013 20130101; G02B 2027/0141 20130101; B60R 1/00 20130101 |
International
Class: |
G06F 3/01 20060101
G06F003/01; B60R 1/00 20060101 B60R001/00; G02B 27/01 20060101
G02B027/01 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 20, 2014 |
TW |
103105732 |
Claims
1. A head-up display, comprising: a display panel configured to
emit an image beam; a non-mechanical focusing lens disposed on a
transmission path of the image beam and generating an image from
the image beam; and a determining unit electrically connected to
the non-mechanical focusing lens and configured to adjust a focal
length of the non-mechanical focusing lens according to a sensing
signal, so as to change an image distance from the image to an eye
of a user.
2. The head-up display as claimed in claim 1, wherein the
non-mechanical focusing lens comprises a focal-length-changeable
lens electrically connected to the determining unit and disposed on
the transmission path of the image beam, wherein the
focal-length-changeable lens is a liquid lens or a liquid crystal
lens.
3. The head-up display as claimed in claim 2, wherein the
non-mechanical focusing lens comprises a focal-length-changeable
lens array electrically connected to the determining unit and
disposed on the transmission path of the image beam, wherein the
focal-length-changeable lens array is a liquid lens array or a
liquid crystal lens array.
4. The head-up display as claimed in claim 2, wherein the
non-mechanical focusing lens further comprises at least one
fixed-focus optical device disposed on the transmission path of the
image beam.
5. The head-up display as claimed in claim 1, wherein the
determining unit is configured to be electrically connected to a
speedometer of a car, the sensing signal is a car speed signal from
the speedometer, and the determining unit is configured to adjust
the focal length of the non-mechanical focusing lens according to
the car speed signal from the speedometer; when a speed of the car
is at a first speed, the non-mechanical focusing lens adjusts the
image distance to a first numerical value; and when the speed of
the car is at a second speed, the non-mechanical focusing lens
adjusts the image distance to a second numerical value, wherein the
first speed is lower than the second speed, and the first numerical
value is smaller than the second numerical value.
6. The head-up display as claimed in claim 5, wherein when the
speed of the car increases from the first speed toward the second
speed, the image distance increases from the first numerical value
toward the second numerical value; and when the speed of the car
decreases from the second speed toward the first speed, the image
distance decreases from the second numerical value toward the first
numerical value.
7. The head-up display as claimed in claim 1, further comprising an
eyeball tracking apparatus electrically connected to the
determining unit, wherein the sensing signal is an image signal
from the eyeball tracking apparatus, and the eyeball tracking
apparatus is configured to track an eyeball of the user, wherein
the determining unit is configured to determine a direction change
of the user's eyeball according to the image signal; when the
determining unit determines that the user's eyeball looks down, the
non-mechanical focusing lens adjusts the image distance to a first
numerical value; and when the determining unit determines that the
user's eyeball looks forward, the non-mechanical focusing lens
adjusts the image distance to a second numerical value, wherein the
first numerical value is smaller than the second numerical
value.
8. The head-up display as claimed in claim 7, wherein when the
eyeball rotates from downward to upward, the image distance
gradually increases, and when the eyeball rotates from upward to
downward, the image distance gradually decreases.
9. The head-up display as claimed in claim 1, further comprising a
user interface electrically connected to the determining unit,
wherein the sensing signal is an operation signal from the user
interface, and the determining unit is configured to adjust the
focal length of the non-mechanical focusing lens according to the
user's operation on the user interface.
10. The head-up display as claimed in claim 1, further comprising a
combiner disposed on the transmission path of the image beam from
the non-mechanical focusing lens, wherein the combiner reflects at
least a portion of the image beam to the user's eye.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Taiwan
application serial no. 103105732, filed on Feb. 20, 2014. The
entirety of the above-mentioned patent application is hereby
incorporated by reference herein and made a part of this
specification.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a display, and more particularly,
to a head-up display.
[0004] 2. Description of Related Art
[0005] In modern society, requirements for vehicles include not
only those for the vehicles' performance, and attention has also
begun to be paid to the vehicles' interior and safety equipments.
With the help of technology products nowadays (e.g. in-car voice
navigation system, voice-based collision warning system, etc.), the
incidence of accidents caused by drivers in states such as
long-time drowsy driving, distracted and so on has indeed dropped.
In the meantime, however, since a non-voice information display
apparatus is generally mounted on a dashboard, when the driver
lowers their head to watch the apparatus, driving safety is likely
to be affected.
[0006] A head-up display (HUD) displays the information desired by
the driver in front of the driver, so that the driver does not have
to lower or turn their head distractedly, which thus enhances
driving safety. Nonetheless, while driving a car, the driver
focuses their eye at different distances at different car speeds.
In general, in high-speed driving (e.g. driving on a highway), the
driver focuses their eye at a further distance in front of the car;
in low-speed driving (e.g. driving in an urban area), the driver
has their eye on road conditions within a shorter distance in front
of the car. However, in the current head-up display, an image
distance between an image generated by the head-up display and the
driver's eye is fixed. Accordingly, whether in high-speed or
low-speed driving, if the driver intends to view the information
shown by the head-up display, they have to spend time focusing
their eye at the image distance at which the image is located. Such
time for focusing the eye delays the time that the driver notices
the road conditions in front of the car.
[0007] U.S. Pat. No. 6,014,259 discloses a zoom lens including a
liquid lens, wherein a focal length of the zoom lens is variable by
changing a shape of the liquid lens. U.S. Pat. No. 7,126,583
discloses adjustment of a head-up display. U.S. Pat. No. 8,031,406
discloses a head-up display for vehicle.
SUMMARY OF THE INVENTION
[0008] The invention provides a head-up display, the head-up
display being capable of adjusting an image distance from an image
generated by the head-up display to a user's eye, thereby enabling
the user to more quickly focus their eye on information displayed
on the head-up display.
[0009] Other objectives and advantages of the invention are further
illustrated by the technical features disclosed in the
invention.
[0010] To achieve one of, a part of or all of the above objectives
or other objectives, an embodiment of the invention provides a
head-up display including a display panel, a non-mechanical
focusing lens and a determining unit. The display panel is
configured to emit an image beam. The non-mechanical focusing lens
is disposed on a transmission path of the image beam and generates
an image from the image beam. The determining unit is electrically
connected to the non-mechanical focusing lens and configured to
adjust a focal length of the non-mechanical focusing lens according
to a sensing signal, so as to change an image distance from the
image to an eye of a user.
[0011] In an embodiment of the invention, the non-mechanical
focusing lens includes a focal-length-changeable lens electrically
connected to the determining unit and disposed on the transmission
path of the image beam, wherein the focal-length-changeable lens is
a liquid lens or a liquid crystal lens.
[0012] In an embodiment of the invention, the non-mechanical
focusing lens includes a focal-length-changeable lens array
electrically connected to the determining unit and disposed on the
transmission path of the image beam, wherein the
focal-length-changeable lens array is a liquid lens array or a
liquid crystal lens array.
[0013] In an embodiment of the invention, the non-mechanical
focusing lens further includes at least one fixed-focus optical
device disposed on the transmission path of the image beam.
[0014] In an embodiment of the invention, the determining unit is
configured to be electrically connected to a speedometer of a car,
the sensing signal is a car speed signal from the speedometer, and
the determining unit is configured to adjust the focal length of
the non-mechanical focusing lens according to the car speed signal
from the speedometer. When the speed of the car is a first speed,
the non-mechanical focusing lens adjusts the image distance to a
first numerical value. When the speed of the car is a second speed,
the non-mechanical focusing lens adjusts the image distance to a
second numerical value, wherein the first speed is lower than the
second speed, and the first numerical value is smaller than the
second numerical value.
[0015] In an embodiment of the invention, when the speed of the car
increases from the first speed toward the second speed, the image
distance increases from the first numerical value toward the second
numerical value. When the speed of the car decreases from the
second speed toward the first speed, the image distance decreases
from the second numerical value toward the first numerical
value.
[0016] In an embodiment of the invention, the head-up display
further includes an eyeball tracking apparatus electrically
connected to the determining unit, wherein the sensing signal is an
image signal from the eyeball tracking apparatus. The eyeball
tracking apparatus is configured to track an eyeball of the user,
wherein the determining unit is configured to determine a direction
change of the eyeball of the user according to the image signal.
When the determining unit determines that the eyeball of the user
looks down, the non-mechanical focusing lens adjusts the image
distance to the first numerical value. When the determining unit
determines that the eyeball of the user looks forward, the
non-mechanical focusing lens adjusts the image distance to the
second numerical value, wherein the first numerical value is
smaller than the second numerical value.
[0017] In an embodiment of the invention, when the eyeball rotates
from downward to upward, the image distance gradually increases;
when the eyeball rotates from upward to downward, the image
distance gradually decreases.
[0018] In an embodiment of the invention, the head-up display
further includes a user interface electrically connected to the
determining unit, wherein the sensing signal is an operation signal
from the user interface. The determining unit is configured to
adjust the focal length of the non-mechanical focusing lens
according to the user's operation on the user interface.
[0019] In an embodiment of the invention, the head-up display
further includes a combiner disposed on the transmission path of
the image beam from the non-mechanical focusing lens, wherein the
combiner reflects at least a portion of the image beam to the eye
of the user.
[0020] The embodiments of the invention achieve at least one of the
following advantages or effects. The head-up display of the
embodiments of the invention includes the non-mechanical focusing
lens, and the determining unit adjusts the focal length of the
non-mechanical focusing lens according to the sensing signal, so as
to change the image distance from the image on the display panel to
the user's eye. Therefore, the time for focusing the user's eye on
the image is reduced, thus improving driving safety. In addition,
due to the employment of the non-mechanical focusing lens for
adjusting the focal length, the adjustment time for the focal
length is shorter. Moreover, vibration and noise are suppressed
during the focusing, and sway of the car during travel has less
influence on the effect of the focusing. Thus, the lens is enhanced
in reliability and life span.
[0021] Other objectives, features and advantages of the invention
will be further understood from the further technological features
disclosed by the embodiments of the invention wherein there are
shown and described preferred embodiments of this invention, simply
by way of illustration of modes best suited to carry out the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1A and FIG. 1B are schematic diagrams of structures of
a head-up display according to an embodiment of the invention at
two different image distances.
[0023] FIG. 2A and FIG. 2B are schematic diagrams of structures of
a head-up display according to another embodiment of the invention
at two different image distances.
[0024] FIG. 3A and FIG. 3B are schematic diagrams of structures of
a head-up display according to still another embodiment of the
invention at two different image distances.
[0025] FIG. 4 is a schematic diagram of a structure of a head-up
display according to yet still another embodiment of the
invention.
[0026] FIG. 5 is a schematic diagram of a structure of a head-up
display according to yet still another embodiment of the
invention.
[0027] FIG. 6 is a schematic diagram of a structure of a head-up
display according to yet still another embodiment of the
invention.
DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS
[0028] In the following detailed description of the preferred
embodiments, reference is made to the accompanying drawings which
form a part hereof, and in which are shown by way of illustration
specific embodiments in which the invention may be practiced. In
this regard, directional terminology, such as "top," "bottom,"
"front," "back," etc., is used with reference to the orientation of
the Figure(s) being described. The components of the present
invention can be positioned in a number of different orientations.
As such, the directional terminology is used for purposes of
illustration and is in no way limiting. On the other hand, the
drawings are only schematic and the sizes of components may be
exaggerated for clarity. It is to be understood that other
embodiments may be utilized and structural changes may be made
without departing from the scope of the present invention. Also, it
is to be understood that the phraseology and terminology used
herein are for the purpose of description and should not be
regarded as limiting. The use of "including," "comprising," or
"having" and variations thereof herein is meant to encompass the
items listed thereafter and equivalents thereof as well as
additional items. Unless limited otherwise, the terms "connected,"
"coupled," and "mounted" and variations thereof herein are used
broadly and encompass direct and indirect connections, couplings,
and mountings. Similarly, the terms "facing," "faces" and
variations thereof herein are used broadly and encompass direct and
indirect facing, and "adjacent to" and variations thereof herein
are used broadly and encompass directly and indirectly "adjacent
to". Therefore, the description of "A" component facing "B"
component herein may contain the situations that "A" component
directly faces "B" component or one or more additional components
are between "A" component and "B" component. Also, the description
of "A" component "adjacent to" "B" component herein may contain the
situations that "A" component is directly "adjacent to" "B"
component or one or more additional components are between "A"
component and "B" component. Accordingly, the drawings and
descriptions will be regarded as illustrative in nature and not as
restrictive.
[0029] FIG. 1A and FIG. 1B are schematic diagrams of structures of
a head-up display according to an embodiment of the invention at
two different image distances. Referring to FIG. 1A and FIG. 1B, a
head-up display 100 of the embodiment includes a display panel 110,
a non-mechanical focusing lens 120 and a determining unit 130. The
display panel 110 is configured to emit an image beam 112. In the
embodiment, the display panel 110 is, for example, a liquid crystal
display panel, an organic light-emitting diode display panel, a
light-emitting diode display panel, a plasma display panel or any
other suitable display panel. The non-mechanical focusing lens 120
is disposed on a transmission path of the image beam 112 and
generates an image 114 from the image beam 112.
[0030] In the embodiment, the head-up display 100 further includes
a combiner 140 disposed on the transmission path of the image beam
112 from the non-mechanical focusing lens 120. The combiner 140
reflects at least a portion of the image beam 112 to a user's eye
50 in a driver's seat of a car, and the combiner 140 allows a light
62 from a windshield 60 of the car to pass therethrough to be
transmitted to the user's eye 50. For example, the light 62 emitted
from a background object 61 in front of the windshield 60 of the
car is transmitted to the user's eye 50 through the windshield 60
and the combiner 140 in sequence. In the embodiment, the combiner
140 is a partially transmissive, partially reflective mirror, such
as a transflective mirror. In addition, the combiner 140 has
optical magnification capability. However, the invention is not
limited thereto. In the embodiment, the head-up display 100 is
disposed between a dashboard and the windshield 60 of the car, or
at least a portion of the head-up display 100 is embedded at the
rear of the dashboard.
[0031] The determining unit 130 is electrically connected to the
non-mechanical focusing lens 120, and is configured to adjust a
focal length of the non-mechanical focusing lens 120 according to a
sensing signal S, so as to change an image distance D from the
image 114 to the user's eye 50.
[0032] In an embodiment, the non-mechanical focusing lens 120
includes a focal-length-changeable lens 122 electrically connected
to the determining unit 130 and disposed on the transmission path
of the image beam 112, wherein the focal-length-changeable lens 122
is a liquid lens or a liquid crystal lens. The liquid lens is, for
example, a dielectric liquid lens, and droplet deformation of the
liquid lens is controlled by means of voltage, thereby changing a
curvature of a lens surface to achieve a focusing effect. The
dielectric liquid lens has a colorless transparent silicone oil
(dimethylsiloxane) structure, and the silicone oil is packaged in
an immiscible alcohol solution. However, the invention is not
limited thereto. Moreover, a material of the liquid crystal lens
is, for example, nematic liquid crystal (NLC). The NLC is a liquid
composed of elongated or disc-shaped molecules. The liquid crystal
lens is driven during powered on, and a driving signal may be
fine-tuned to create an electric field strength that generates a
desired refractive index gradient as well as a desired optical
refractive index. In addition, the alignment of the NLC molecules
may be changed by adjusting a frequency of an electric signal.
Nonetheless, the invention is not limited thereto.
[0033] In another embodiment, the non-mechanical focusing lens 120
further includes a fixed-focus optical device 124 (FIG. 1A shows an
invariable-focus lens 124 as an example) disposed on the
transmission path of the image beam 112, wherein the fixed-focus
optical device 124 is a refractive lens or a reflective mirror. In
the embodiment, the fixed-focus optical device 124 is disposed
between the focal-length-changeable lens 122 and the display panel
110. However, in other embodiments, the focal-length-changeable
lens 122 may be disposed between the fixed-focus optical device 124
and the display panel 110.
[0034] In the embodiment, the determining unit 130 is configured to
be electrically connected to a speedometer 70 of a car, and the
sensing signal S is a car speed signal from the speedometer 70. For
example, the speedometer 70 is configured to measure a rotational
speed of wheels of the car, and then convert the rotational speed
into a speed of the car. The determining unit 130 is configured to
adjust the focal length of the non-mechanical focusing lens 120
according to the car speed signal from the speedometer 70. When the
speed of the car is at a first speed, the non-mechanical focusing
lens 120 adjusts the image distance D to a first numerical value D1
(as shown in FIG. 1A). When the speed of the car is at a second
speed, the non-mechanical focusing lens 120 adjusts the image
distance D to a second numerical value D2 (as shown in FIG. 1B),
wherein the first speed is lower than the second speed, and the
first numerical value D1 is smaller than the second numerical value
D2. In the embodiment, when the speed of the car increases from the
first speed toward the second speed, the image distance D increases
from the first numerical value D1 toward the second numerical value
D2. When the speed of the car decreases from the second speed
toward the first speed, the image distance D decreases from the
second numerical value D2 toward the first numerical value D1.
[0035] In an embodiment, the fixed-focus optical device 124 has a
focal length of 400 mm, and the focal-length-changeable lens 122
has a variable focal length from 425 mm to infinity. When the
focal-length-changeable lens 122 has an infinite focal length, the
optical effect of the focal-length-changeable lens 122 is
equivalent to that of a plate glass. At this moment, the focal
length of the entire non-mechanical focusing lens 120 is equal to
the focal length of the fixed-focus optical device 124, which is
400 mm, and the resulting image distance D is 1.46 m. Here, the
image 114 is located not far from the windshield 60. When the
focal-length-changeable lens 122 has a focal length of 425 mm, the
focal length of the entire non-mechanical focusing lens 120 is, for
example, 208 mm, and the resulting image distance D is 10 m. Here,
the image 114 is located far away in front of the car. For example,
since the focal length of the focal-length-changeable lens 122 is
adjustable between 425 mm and infinity, the resulting image
distance D may be continuously adjusted between 1.46 to 10 m.
Nonetheless, the embodiment is provided for exemplary purposes only
but is not intended to limit the invention.
[0036] The head-up display 100 of the embodiment includes the
non-mechanical focusing lens 120, and the determining unit 130
adjusts the focal length of the non-mechanical focusing lens 120
according to the sensing signal S, so as to change the image
distance D from the image 114 on the display panel 110 to the
user's eye 50. Accordingly, the time for focusing the user's eye 50
on the image 114 is reduced, thus improving driving safety. In
addition, due to the employment of the non-mechanical focusing lens
120 for adjusting the focal length, the adjustment time for the
focal length is shorter (e.g., less than 1 second, which is shorter
than the time spent by a mechanical apparatus). Moreover, vibration
and noise are suppressed during the focusing, and sway of the car
during driving has less influence on the effect of the focusing,
and therefore the lens is enhanced in reliability and life span.
Another advantage of employing the liquid lens or liquid crystal
lens is that a focusing range may be continuous, i.e. the image
distance D is continuously adjustable. Hence, there is no need to
dispose two or more head-up displays having different image
distances in the car. Accordingly, the structure of the head-up
display 100 of the embodiment occupies less space in the car.
[0037] FIG. 2A and FIG. 2B are schematic diagrams of structures of
a head-up display according to another embodiment of the invention
at two different image distances. Referring to FIG. 2A and FIG. 2B,
a head-up display 100a of the embodiment is similar to the head-up
display 100 in FIG. 1A and FIG. 1B, and the difference is mainly
described in the following respects. In the embodiment, the head-up
display 100a further includes an eyeball tracking apparatus 150,
for example, a video camera 150 as shown in FIG. 2A and FIG. 2B.
The eyeball tracking apparatus 150 is electrically connected to the
determining unit 130, wherein a sensing signal S1 is an image
signal from the eyeball tracking apparatus 150, and the eyeball
tracking apparatus 150 is configured to track an eyeball of the
user's eye 50 in the driving seat of the car. The determining unit
130 is configured to determine a direction change of the user's
eyeball according to the image signal (i.e. the sensing signal S1).
When the determining unit 130 determines that the user's eyeball
looks down, the non-mechanical focusing lens 120 adjusts the image
distance D to the first numerical value D1. When the determining
unit 130 determines that the user's eyeball looks forward, the
non-mechanical focusing lens 120 adjusts the image distance D to
the second numerical value D2, wherein the first numerical value D1
is smaller than the second numerical value D2. Such design is on
the following basis: the user's eyeball looks down usually when
viewing a near road condition at a lower car speed, and thus a
shorter image distance D (such as the image distance D having the
first numerical value D1) is employed. In another respect, the
user's eyeball looks forward usually when viewing a distant road
condition at a higher car speed, and thus a longer image distance D
(such as the image distance D having the second numerical value D2)
is employed. In addition, in the embodiment, when the user's
eyeball rotates from downward to upward, the image distance D
gradually increases; when the user's eyeball rotates from upward to
downward, the image distance D gradually decreases.
[0038] FIG. 3A and FIG. 3B are schematic diagrams of structures of
a head-up display according to still another embodiment of the
invention at two different image distances. Referring to FIG. 3A
and FIG. 3B, a head-up display 100b of the embodiment is similar to
the head-up display 100 in FIG. 1A and FIG. 1B, and the difference
is mainly described in the following respects. In the embodiment,
the head-up display 100b further includes a user interface 160
electrically connected to the determining unit 130, wherein a
sensing signal S2 is an operation signal from the user interface
160. The determining unit 130 is configured to adjust the focal
length of the non-mechanical focusing lens 120 according to the
user's operation on the user interface 160. In other words, the
user decide themselves through the operation on the user interface
160 whether the numerical value of the accustomed image distance D
is the first numerical value D1, the second numerical value D2 or
any other numerical value between the first numerical value D1 and
the second numerical value D2. The user interface 160 is, for
example, a touch panel, a button, a knob or any other appropriate
device that may be operated by the user.
[0039] FIG. 4 is a schematic diagram of a structure of a head-up
display according to yet still another embodiment of the invention.
Referring to FIG. 4, a head-up display 100c of the embodiment is
similar to the head-up display 100 in FIG. 1A and FIG. 1B, and the
difference is mainly described in the following respects. In the
head-up display 100c of the embodiment, the focal-length-changeable
lens 122 in FIG. 1A is displaced by a focal-length-changeable lens
array 122c. The focal-length-changeable lens array 122c is disposed
on the transmission path of the image beam 112, wherein the
focal-length-changeable lens array 122c is, for example, a liquid
lens array or a liquid crystal lens array, and the
focal-length-changeable lens array 122c includes a plurality of
variable-focus microlenses 123 arranged in a two-dimensional
array.
[0040] FIG. 5 is a schematic diagram of a structure of a head-up
display according to yet still another embodiment of the invention.
Referring to FIG. 5, a head-up display 100d of the embodiment is
similar to the head-up display 100 in FIG. 1A and FIG. 1B, and the
difference is mainly described in the following respects. The
head-up display 100d does not include the combiner 140 that is
separated from the windshield 60 as shown in FIG. 1A. The
non-mechanical focusing lens 120 projects the image beam 112 onto
the windshield 60. In the embodiment, an optical film 170 is
adhered to the windshield 60. The optical film 170 reflects at
least a portion of the image beam 112 to the user's eye 50, and
allows the light 62 from the windshield 60 to pass through the
optical film 170 to the user's eye 50. In the embodiment, the
optical film 170 is a partially transmissive, partially reflective
film, such as a transflective film.
[0041] In another embodiment, as shown in FIG. 6, a head-up display
100e does not employ the optical film 170, the non-mechanical
focusing lens 120 projects the image beam 112 directly onto the
windshield 60, and the windshield 60 reflects at least a portion of
the image beam 112 to the user's eye 50.
[0042] In summary, the embodiments of the invention achieve at
least one of the following advantages or effects. The head-up
display of the embodiments of the invention includes the
non-mechanical focusing lens, and the determining unit adjusts the
focal length of the non-mechanical focusing lens according to the
sensing signal, so as to change the image distance from the image
on the display panel to the user's eye. Therefore, the time for
focusing the user's eye on the image is reduced, thus improving
driving safety. In addition, due to the employment of the
non-mechanical focusing lens for adjusting the focal length, the
adjustment time for the focal length is shorter. Moreover,
vibration and noise are suppressed during the focusing, and sway of
the car during travel has less influence on the effect of the
focusing, and therefore the lens is enhanced in reliability and
life span.
[0043] The foregoing description of the preferred embodiments of
the invention has been presented for purposes of illustration and
description. It is not intended to be exhaustive or to limit the
invention to the precise form or to exemplary embodiments
disclosed. Accordingly, the foregoing description should be
regarded as illustrative rather than restrictive. Obviously, many
modifications and variations will be apparent to practitioners
skilled in this art. The embodiments are chosen and described in
order to best explain the principles of the invention and its best
mode practical application, thereby to enable persons skilled in
the art to understand the invention for various embodiments and
with various modifications as are suited to the particular use or
implementation contemplated. It is intended that the scope of the
invention be defined by the claims appended hereto and their
equivalents in which all terms are meant in their broadest
reasonable sense unless otherwise indicated. Therefore, the term
"the invention" or the like does not necessarily limit the claim
scope to a specific embodiment, and the reference to particularly
preferred exemplary embodiments of the invention does not imply a
limitation on the invention, and no such limitation is to be
inferred. The invention is limited only by the spirit and scope of
the appended claims. The abstract of the disclosure is provided to
comply with the rules requiring an abstract, which will allow a
searcher to quickly ascertain the subject matter of the technical
disclosure of any patent issued from this disclosure. It is
submitted with the understanding that it will not be used to
interpret or limit the scope or meaning of the claims. Any
advantages and benefits described may not apply to all embodiments
of the invention. It should be appreciated that variations may be
made in the embodiments described by persons skilled in the art
without departing from the scope of the invention as defined by the
following claims. Moreover, no element and component in the present
disclosure is intended to be dedicated to the public regardless of
whether the element or component is explicitly recited in the
following claims.
* * * * *